Method of grinding crank shafts



Sept 1933- A. P. STEINER METHOD OF GRINDING CRANK SHAFTS Filed Dec. 21,1929 INVENTOR Arno. F Jfe/ncr.

TTORNEY Patented Sept. 5, 1933 v UNITED STATES PATENT OFFICE 1,925,911METHOD OF GRINDING CRANK SHAFTS Application December 21, 1929 Serial No.415,836..

6 Claims. (Cl. 51-4578) This application is a division in part of thecopending application of Amos P. Steiner, Paul Stoner, and Charles P.Harrison for crank grinding machines, Serial No. 126,583, filed August2, 1926, and is directed to the method of grinding crank shafts. 7

An object of theinvention is to provide a method for grinding crankshafts in which all the pins on a shaft may be ground onone ma- 10 chinewithout changing the'set-upor arrange-.

ment of the fixtures.

In grinding crank shafts as heretofore practiced it was necessary tohave a separate machine for each pair of pins, each machine was set-upto grind a certain pair of pins and could not be used for any other setwithout shifting the work rest around. In grinding crank shafts in largequantities, such as is necessary in modern mass production, such methodswere costly and slow.

0 By moving the work rest from the work table where it has beenheretofore placed and mounting it so that it will always be in grindingposition, i. e. always in the plane of rotation of the grinding wheel, aset-up is provided which does not need to be changed at all so that allthe pins on a shaft may be ground on a single machine. This results in agreat saving in the handling of the work as Well as providing a greatsaving in-the number of machines as heretofore required.

My method consists in moving the work carriage so as to bring the pinsinto position between the wheel and a work rest. The work rest-and thewheel are moved against the pin which is in position; the pin is groundand the work rest and the wheel are returned to inoperative position sothat the carriage may be moved between the work rest and the wheel tobring another pin on the crank shaft in the same plane into grindingposition before the wheel. When all the pins in a single plane have beenground the work rest and the grinding wheel are withdrawn and the crankis indexed so as to bring another pair of pins in position to be ground.The crank shaft is held in chucks and is gripped at a point eccentricwith respect to its axis of rotation so that the crank always rotatesaround an axis which is the axis of the pin which is being ground. Eachpair of pins is ground and the shaft rotated to bring the adjacent pairto position until all of the pins are ground. After grinding each pinthe work restand the grinding wheel are each withdrawn to permit thework carriage freely to pass between the grinding wheel and the workrest; the work rest being positioned in the plane of the, grinding wheelis always in position to hold a pin when the pin has been brought to.grinding position.

The drawing 'is a diagrammatic illustration of the various positions ofthe grinding wheel, the crankshaft and its pins and the back rest.

Referring to the drawing which is made a part hereof-and on whichsimilar reference characters indicate similar parts,

Figure I shows a conventional grinding wheel anda crank shaft with pin 1or 6 in grinding position,

Figure 1A is a plan view showing the grinding wheel and work rest inposition to grind pin No. 7 1 on a crank shaft, Y

Figure 1B is a plan View showing the wheel and the work rest withdrawnto allow the crank shaft to be moved to bring pin No. 6 into grindingposition,

Figure 10 shows the grinding wheel, the work rest and the crank shaft inposition to grind pin No. 6 on the crank shaft,

Figure 2 'is a view in elevation of the grinding wheel and the crankshaft showing pin No. 2 or 5 in position to be ground,

Figure 2A shows the grinding wheel and work rest withdrawn to permit acrank shaft to be moved to position at which pin No. 2 may be ground,

Figure 2B shows the grindingwheel and back rest in position to grind pinNo. 2,

Figure 2C shows the grinding wheel and the back rest withdrawn from pin2 to permit traversal of the work carriage.

Figure 2D shows a grinding wheel and work rest in position to grind pinNo. 5,

Figure 3 is an end elevation of the grinding wheel and crank shaft so asto show the relative positions of the grinding wheel and the 5 crankshaft when grinding either pin No. 3 or No. 4, a

Figure 3A shows the grinding wheel and the back rest withdrawn to permittraversal of the crank shaft to bring pin No. 3 in position to beground,

Figure 3B shows the grinding wheel and back rest in position to grindpin No. 3,

Figure 30 shows the grinding wheel and back rest withdrawn to permittraversal of the crank shaft to position the grind pin No. 4.

Figure 3D shows the grinding wheel and back rest in position to grindpin No. 4, and

Figure 3E shows the grinding wheel .and parts withdrawn to permit thecrank shaft to be withalways rotate about the pins which are beingound.

A grinding wheel 13 is mounted so as to move into and out of grindingposition to grind the work and a work rest 14 is movable toward and fromthe work to hold the workagainst the grinding wheel.

As soon as a pin is ground to size the work rest and the grinding wheelare retracted and the work is traversed between them to bring the otherpin in the same plane into position after which the grinding operationis repeated. I The long arrows 15. indicate the direction in which thework carriage and the crank shaft are about to move. The short arrows 16and 17 indicate the directions in which the grinding wheel and'the workrest respectively have just moved. I

It will be obvious to those skilled in the art that various changes maybe made in my device without departing from the spirit of the inventionand therefore I do not limit myself to what is shown in the drawing anddescribed in the specification, but only as indicated in the appendedclaims.

Having thus fully described my said invention, what I claim as new anddesire to secure by Letters Patent, is:

1. The method of grinding the pins of multiple throw crank shafts whichconsists in grinding first the pin or pins in a given plane, rotat ingthe shaft to bring other pin or pins into the axis of rotation of saidpins, grinding the pin or pins while supporting said shaft against thethrust of the grinding action, withdrawing the support and the grindersufficiently far from the shaft to permit free indexing of the shaftfrom the position for grinding one pin to the position for grindinganother pin, all of the grinding being performed while maintaining agiven grinding set-up of the machine, substantially as set forth. I

2. The method of grinding the pins of multiple throw crank shafts in asingle machine which consists in grinding first the pin or pins in agiven plane, rotating the shaft to bring other pin or pins into the axisof rotation of said pins, grinding the pin or pins while supporting saidshaft against the thrust of the grinding action, withdrawing the supportand the grinder sufficiently far from the shaft to permit free indexingof the shaft from the position for grinding one pin to the position forgrinding another pin, all of the grinding being performed whilemaintaining a given grinding set-up of the machine, substantially as setforth.

3. The method of grinding the pins of crankshafts which consists infirst grinding all pins which are in axial alignment with eachother,rotating the shaft through a partial revolution to bring another set ofaxially aligned pins into grinding relation with the grinding wheel,grinding this set of pins and then 'rotatingtheshaft to bring other sets'of axially aligned pins into grinding relation with the grinding wheeland grinding them, grinding of all of said pins being accomplished whilemaintaining a given grinding set-up of -the machine, substantially asset forth.

4. The'method of grinding the pins of crankshafts in a machine having awheel which comprises grinding one set of pins, rotating the shaft toanother set of such pins and grinding them and continuing the rotationand the grinding of the several sets of pins, indexing the shaft axiallybetween each grinding operation and withdrawing the back rest betweeneach grinding operation sufficiently far to permit free rotation andfree axial indexing of the shaft while maintaining the original grindingset-up" of the machine, substantially as set forth. v

5. The method of operating a grinding machine having a back-rest and agrinding wheel for grinding the pins of crankshafts which consists ingrinding all of the pins in a given plane, rotating the shaft to bring aset of pins in another plane in correct rotary position for grindingthem, grinding these pins, successively rotating the shaft to bringother sets of pins into grinding position and successively grindingthem, withdrawing the back-rest a distance sufficient to permitfreerotary and axial indexing of the shaft, grinding of the entire shaftbeing effected while maintaining a given grinding setup of the machinewhereby all of the pins on a crankshaft may be ground by a singlemachine,

substantially as set forth.

